• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.395-400
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• 2017

Coke strength was increased by adding ash-free coal (AFC) binder. In this study, the effect of the AFC binder on the physical and chemical properties of coke was experimentally investigated to understand the molecular mechanism for the improved coke strength. For reduced $CO_2$ emission in steelmaking industry, torrefied biomass fuel mixed with coal binder is also considered. The interface between the base coal and AFC was thus examined using Scanning Electron Microscope (SEM). The coke strength was commonly measured by performing the indirect tensile test and Nuclear Magnetic Resonance (NMR) spectroscopy in $^1H$ and $^{13}C$ modes. For comprehensive mechanism study of the enhanced coke strength thus obtained, ordinary coal for thermal power plant use was carbonized with AFC for subsequent SEM examination. The NMR spectroscopy results of coke samples positively revealed that the tensile strength was proportional to the average number of aromatic rings.

• Journal of Aquaculture
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• v.11 no.1
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• pp.99-103
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• 1998

Artemia often observed as a co-existing organism in the mass culture tank of marine rotifer. The rotifer and Atremia are commonly used as food organisms in the marine fish larvae rearing. In this study, interspecific relation between the rotifer Brachionus rotundiformis (formely called S-type) and anostracan Artemia of the two developmental stages (0 and 19 day old after hatching) were investigated in the larboratory. The population growth of B. rotundiformis and one of the stage (nauplius or adult) of Artemia in mixed culture was compared with that of each single species culture. Culture period was 16 days. Every two days, the number of organisms in each species was counted and transferred to a fresh medium containing $7{\times}10^5$cells/ml of food Nannochloropsis oculata. Culture volume, temperature, salinity and photoperiod were set at 40ml, $25^{\circ}C.$, 22ppt and 24h all dark except to observation time, respectively. The rotifer population growth was greatly decreased by co-existence with Artemia. The coexisting Artemia suppressed the rotifer population growth due to it's high filtering speed for food (N. oculata). This study suggested that contamination by Artemia must be prevented for the stable rotifer production in the rotifer mass culture tank.

• Journal of Bio-Environment Control
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• v.5 no.1
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• pp.89-97
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• 1996

Oriental melon and watermelon plants were cultivated in the soil treated with bioceramics in a greenhouse during summer season from June 1st to August 20th, 1995. Two application methods were employed, one was a mixed treatment of soil and bioceramics, and the other was a spray treatment of bioceramic solution on the stems and leaves. And two types of bioceramics were also stopped by five levels. In order to analyze the bioceramic effect on oriental melon and watermelon, the growth rate of stems, leaves and fruits were measured in the greenhouse. After harvest, the sweetness of fruits was measured and the freshness of fruits based on the storage period was tested by human taste and smell sense. The results are summarized as follows. 1. The growth rates of stems, leaves and fruits of oriental melon and watermelon were the largest in the bioceramic treatment of No. 3. 2. The density of oriental melon and watermelon was the largest in the bioceramic treatment of No. 3 and No. 2 respectively. 3. The Brix number of watermelon was 10.6 in non-bioceramic treatment and 11.5 in the bioceramic treatment of No. 2, and that of oriental melon was 8.6 in non-bioceramic treatment and 12.3 in the bioceramic treatment of No. 2. 4. The storage duration of watermelon treated with bioceramics was about 50 days in the condition of the ambient temperature of 25-3$0^{\circ}C$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1139-1146
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• 2012

An alternative approach for topology optimization of steady incompressible Navier-Stokes flow problems is presented by using P1 nonconforming finite elements. This study is the extended research of the earlier application of P1 nonconforming elements to topology optimization of Stokes problems. The advantages of the P1 nonconforming elements for topology optimization of incompressible materials based on locking-free property and linear shape functions are investigated if they are also valid in fluid equations with the inertia term. Compared with a mixed finite element formulation, the number of degrees of freedom of P1 nonconforming elements is reduced by using the discrete divergence-free property; the continuity equation of incompressible flow can be imposed by using the penalty method into the momentum equation. The effect of penalty parameters on the solution accuracy and proper bounds will be investigated. While nodes of most quadrilateral nonconforming elements are located at the midpoints of element edges and higher order shape functions are used, the present P1 nonconforming elements have P1, {1, x, y}, shape functions and vertex-wisely defined degrees of freedom. So its implentation is as simple as in the standard bilinear conforming elements. The effectiveness of the proposed formulation is verified by showing examples with various Reynolds numbers.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.317-323
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• 2010

This study aimed to examine a suppression effect of salinity on extension rate of stem elongation of cucumber seedlings (Cucumis sativus L.) grafted with roots of figleaf gourd plant. The effects of application methods, timings, and concentrations of two salt types, sodium chloride (NaCl) and calcium chloride ($CaCl_2$), were compared to untreated control plants. In result, an obvious suppression effect on the excessive elongation of stem was obtained by both sub-irrigated and medium-mixed NaCl salt. An improvement in quality of transplants was also obtained by the sub-irrigated NaCl salt. Foliar-applied NaCl caused visible leaf injury when the concentration was higher than 40 mM; but, with no effect on suppressing the stem elongation. When the NaCl was applied at 7 days after grafting, a higher concentration of NaCl was demanded for suppressing the stem elongation compared to an application at the day of grafting. No effect of the NaCl salt on the fresh weights of 36-day grown plants was observed; but, there was a negative effect on the number of female flowers at a high temperature season. Overall, the NaCl salt was more effective on slowing down the stem elongation and had the lower incidence of leaf injury than the $CaCl_2$ salt.

• Parasites, Hosts and Diseases
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• v.45 no.3
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• pp.213-218
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• 2007

The prevalence of liver and intestinal fluke infections was surveyed on residents of Savannakhet Province, Laos. Fecal specimens were collected from a total of 981 residents in 4 Mekong riverside villages and examined by the Kato-Katz thick smear technique. The results revealed that the overall helminth egg positive rate was 84.2%, and the positive rate for small trematode eggs, including Opisthorchis viverrini, heterophyids, or lecithodendriids, was 67.1 %. To obtain adult flukes, 38 small trematode egg positive cases were treated with a 20-30 mg/kg single dose of praziquantel and purged. Diarrheic stools were then collected from 29 people and searched for helminth parasites using stereomicroscopes. Mixed infections with O. viverrini and 6 kinds of intestinal flukes were found, namely, Haplorchis taichui, Haplorchis pumilio, Haplorchis yokogawai, Prosthodendrium molenkampi, Phaneropsolus bonnei, and echinostomes. The total number of flukes collected was 7,693 specimens (av. no. per treated person; 265.3). The most common species was O. viverrini, followed by H. taichui, P. molenkampi, echinostomes, H. pumilio, P. bonnei, and H. yokogawai. The results indicate that foodborne liver and intestinal fluke infections are prevalent among residents of Savannakhet Province, Laos.

• Journal of Life Science
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• v.22 no.1
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• pp.80-86
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• 2012

This study was conducted to improve quality of takju where natural honey is used to control the ripening fermentation and the amount of sediment derived from takju mash. A koji was prepared using rice starch and Aspergillus awamori var. kawachii. Takju mash was prepared by alcohol fermentation with Saccharomyces cerevisiae and a 3-step addition of steamed rice. The clean part of the mash (CPM) was separated from the sediment at $5^{\circ}C$ and 5% (w/v) of natural honey was added and then ripened for 23 days at 5, 10, or $15^{\circ}C$. Temperature, pH, acidity, and total sugar content showed no significant differences, but a 0.2 percent reduction in alcohol content occurred during storage. However, CPM ripened with honey had a comparatively higher score on sensory evaluation than did immature CPM with added honey added. Takju with 8% alcohol content was prepared by mixing the water from the mixed CPM ripened with honey together with 100, 50, and 25% of the frozen sediment. Several quality characteristics of the takju were checked over 37 days of fermentation at $10^{\circ}C$. The pH was sustained between 4.1 and 4.3, and changes in the number of viable yeast cells, acidity, total sugar amounts, and alcohol content showed similar patterns but differences in scale. Smaller amounts of sediment affected the stability of the takju. Mixing the CPM ripened with natural honey at low temperature moderately reduced the amount of sediment in the mash and resulted in a highly flavorful takju with an extended shelf life.

• Journal of Yeungnam Medical Science
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• v.15 no.2
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• pp.275-285
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• 1998

Sarcoma of the uterus is very rare malignant tumor originating from uterine muscle or connective tissue. We have experienced 20 cases of uterine sarcoma from January 1991 to June 1998. The results were as follows: 1. The pathologic types were 13 cases(65.0%) of leiomyosarcoma, 5 cases(25.0%) of malignant mixed Mullerian tumor, 1 case of rhabdomyosarcoma, and 1 case of angiosarcoma. 2. The average age and parity was 50.2 and 3.7. The chief complaints were irregular vaginal bleeding(35.0%), lower abdominal pain(25.0%), and abdominal mass(25.0%). 3. Nine cases(45.0%) were FIGO stage I, 1 case(5.0%) was stage II, 6 cases(30.0%) were stage III, and 4 cases(20.0%) were stage IV. 4. The survival was from 1.5 months to over 130 months(median 16.5 months), and there was no correlation between survival and FIGO stage or pathologic type. The correlation between survival and number of mitotic figure was incalcurable. 5. CA 125 levels were serially measured as a tumor marker in monitoring patients and the positive rate was 40%. Further study was needed to make a conclusion for usefulness of CA 125 as a tumor marker.

• Journal of the Korean Chemical Society
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• v.54 no.6
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• pp.809-817
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• 2010

The primary purpose of this study was to investigate high school students' conceptual understanding of density for solids and liquids in pure and mixed substances who had preceded formal school science instruction on density and related topics. A concept assessment on density was developed and administered by demonstrative experiments accompanied by a written assessment test method to 120 general high school students in a metropolitan city. The scientific conceptions and alternative conceptions from students' responses were identified and the percentages of them were calculated. Then, their alternative conceptions and implicit theories on density were analyzed. About half of the students couldn't differentiate weight-volume-density and regarded density as an innate property of matter. Furthermore, the greater the number of variables involved in an experimental condition of the question, the more complicated and undifferentiated students' density concepts were. Students employed more improper variables such as particle size, intermolecular distance, surface tension, polarity of the solvent, etc. in explaining counter-intuitive observations. The implications for school science instruction were discussed.

• Korean Journal of Plant Resources
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• v.27 no.5
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• pp.540-545
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• 2014

The Polygonatum odoratum cv. Gungangbeaksea, bred in Gyeongsangnam-Do Agricutural Research & Extension Service, was cultured in vitro for micropropagate rapidly through the culture of rhizome explants ($5{\times}5mm$). The $7{\times}7mm$ explants of adventitious multi-bud clusters (AMC), obtained through the culture of rhizome explants (MS + 3.0 mg/L BA) were cultured on MS media with BA and TDZ. The shoot multiplication was favorable on the MS medium containing 3.0 mg/L TDZ with 2.8 in shoot number. But the formation of AMC was low in all media tested. The explants of AMC were cultured on MS media containing 1.0~5.0 mg/L TDZ and NAA to multiplicate AMC more. The formation of AMC was a little more stimulated on combined MS media of TDZ and NAA, than that with TDZ alone. The multiplication of shoots and AMC was favorable on MS media with 3.0 mg/L TDZ and 5.0 mg/L NAA, and 5.0 mg/L TDZ and 3.0 mg/L NAA. As the concentration of MS salts increased, the formation of AMC was decreased. But the formation of AMC was more stimulated, as the concentration of sucrose increased to 7%. Therefore, the multiplication of shoots and AMC was suitable on media containing 3.0~5.0 mg/L TDZ and NAA, and 7% of sucrose. The explants of AMC were rooted on media with 3.0 mg/L IBA, or 2.0 mg/L NAA with more than 80% in rooting ratio. The plantlets were treated at $5^{\circ}C$ for 8 weeks, and cultured ex vitro for 8 weeks. The survival ratio of plantlets were 100% in vermiculite, and the mixed soil with perlite 1 volumn and vermiculite 1 volumn.